One of typical methods of injecting a large quantity of sample during gas chromatography is a PTV (programmed temperature vaporizer) method with or without a split for discharging the solvent. This method calls for a liner disposed at the injection port, and filling the liner with a filler in order to introduce as much sample as possible into the injection port. When in use, the temperature in the injection port has to be maintained so as not to exceed the boiling point of the solvent for the sample. Said method then calls for injecting a great quantity of sample into the injection port so that the sample is retained in the filler; introducing a great quantity of carrier gas in the state where the temperature is still maintained low so that most of the solvent is discharged through a vent line and that the system becomes a splitless state; and introducing the desired constituent that is trapped in the filler in the liner into a column while increasing the temperature in the injection port. Other than the PTV method, various methods on which research and investigations have conventionally been conducted include the on-column mass injection method, which calls for increasing the temperature of the oven and causing pressure equilibrium of the sample in the column in order to remove only the solvent.
A method which calls for filling a split liner with glass wool, a collector or the like to discharge the solvent presents the possibility of the desired constituent remaining in the filler or being decomposed during the thermal desorption process. It is a common knowledge that decomposition actually occurs with some agricultural chemicals. On the other hand, the on-column mass injection method presents a problem in that it takes a long period of time to remove the solvent. Furthermore, as it is difficult to fulfill the conditions for attaining equilibrium in the column, the desired constituent tends to spread into a wide area, thereby necessitating re-condensation.